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Atlantic/2018/03L/Archive/14
Hurricane Chris Discussion Number 14 Wiki-Hurricanes Forecast Center 11:00 AM EDT Wed Jul 11 2018 Chris became more ragged over the past several hours as some westerly shear from a nearby shortwave trough impacted the system in concert with some dry air intrusion. The eye clouded over on infrared imagery at around 1130Z but remained somewhat apparent on visible channels. Nonetheless, recent data indicate that Chris is attempting to reorganize this morning with some -70°C cloud tops evident in the northern part of its central dense overcast. Since 14Z, the eye has cleared out on both infrared and visible satellite imagery. A microwave pass from 1236Z however indicated that the potent core of Chris was asymmetric, which may make it more difficult for the hurricane to intensify. SAB noted lowering raw satellite intensities in assessing a T5.0/90kt current intensity for Chris at 12Z. SATCON fell to 89kt after reaching as high as 106kt during the overnight hours. UW-CIMSS ADT raw values dropped to Category 1 strength but have rebounded back to around 90kt. As the eye is beginning to clear out once again after clouding over, the intensity for this advisory remains assessed at 90kt in line with satellite estimates. Chris is now tracking briskly to the northeast, and should continue to do so for the next day-and-a-half or so before it begins curving east in the far northern Atlantic around the periphery of a larger extratropical cyclone to its north. Models are in general agreement that Chris will pass near or over Newfoundland's Avalon Peninsula in tomorrow evening. In the meantime, conditions for Chris are supportive of some intensification or maintenance of the current intensity this afternoon, with Chris expected to cross the eastward-moving branch of the Gulf Stream in a few hours where some sea surface temperatures within the storm's fetch a more favorable 27°C. This may allow for some convective fortification over the next few hours before the system hits a sharp thermal oceanic gradient this evening at the northern edge of the Gulf Stream. After that point, baroclinic processes associated with the nearby trough are expected to deepen the cyclone as it transitions into an extratropical cyclone, though this does not necessarily translate directly into a consequent increase in winds. Most dynamical guidance show this deepening, though some models like the HWRF and HMON seem to be a bit over-aggressive in their handling of a threshold Category 4 or strong Category 3. SHIPS guidance shows a steady state system while most early cycle statistical guidance indicates winds strengthening today followed by weakening as the system transitions into an extratropical cyclone. The current intensity forecast shows some strengthening today followed by extratropical transition and more rapid weakening mid-day tomorrow. The intensity forecast below does not effectively convey the possibility for baroclinic intensification between 12/0000Z and 12/1200Z, and a major hurricane in that timeframe cannot be ruled out. FORECAST POSITIONS AND MAX WINDS INIT 11/1500Z 90KT 105MPH 12H 12/0000Z 95KT 110MPH 24H 12/1200Z 90KT 105MPH 36H 13/0000Z 60KT 70MPH...EXTRATROP 48H 13/1200Z 45KT 50MPH...EXTRATROP 72H 14/1200Z...DISSIPATED